.container {
  width: 600px;
  margin: 20px auto;
  height: 200px;
  background-color: #fa4751;
  padding-top: 1px;
}
.el {
  width: 50px;
  height: 50px;
  background: #FFF;
  margin-left: 20px;
  margin-top: 75px;
}

.nav {
  display: flex;
  position: sticky;
  top: 96px;
  z-index: 1;
  background-color: #FFF;
  border-bottom: 1px solid #ccc;
  border-top: 1px solid #ccc;
}

.active {
  background-color: #e8e8e8;
}

.item {
  flex: 1;
  height: 40px;
  line-height: 40px;
  text-align: center;
  font-size: 15px;
}